1. Field of the Invention
The present invention relates generally to siliconcontaining compounds, methods for the preparation of such compounds, and polymers thereof. More particularly, the present invention relates to aromatic amine terminated silicone monomers, oligomers, and polymers thereof.
2. Description of Related Art
Polyimides are widely used in the electronics and aerospace industry, f or example, as coatings, adhesives, and interlevel insulators in integrated circuits, and also to form composites and other structures.
Silicon-containing imides, specifically, silanol- and silyl-terminated aromatic imide oligomers, have been disclosed and claimed in a series of patents assigned to the same assignee as the present application: U.S. Pat. Nos. 5,021,585; 5,075,475; and 5,081,201. These compounds possess good optical properties, good thermo-oxidative stability, resistance to atomic oxygen degradation, good mechanical properties, and good processing characteristics.
Japanese Published Unexamined Patent Application 63-169561 discloses silicone-imide copolymers for flexible printed circuit boards, insulating material for heavy electric machines, carrier tapes, thermal resistant coating material for electric wire, and the like. This patent discloses the preparation of bis(3-aminophenyl)-1,1,3,3-tetramethylsiloxane as an intermediate in the reaction sequence to preparing the polymers of the invention. However, the synthetic route to forming the siloxane follows classical methods and requires several reaction steps.
The monomer bisaminophenyltetramethyl disiloxane is described in two articles, V. H. Kuckertz, Die Makromolekulare Chemie, Vol. 98, pp. 101-108 (1966) and J. C. Bonnet et al, Bulletin de la Societe Chimique de France, Vol. 1972, pp. 3561-3579 (1972).
The first reference describes polyimides prepared from the above monomer which are brittle and less soluble as compared to the aliphatic counterpart. The synthesis of the diamine in both references is through classical nitration chemistry, which most likely gives impure and isomeric monomers.
The second reference describes the diamino monomer, but does not describe polyimides.
Other aromatic polyimide siloxanes are described in another reference, P. P. Policastro et al, "Siloxane Polyimides for Interlevel Dielectric Applications", in the Proceedings of the ACS Division of Polymeric Materials: Science and Engineering, Vol. 59, pp. 209-213 (Los Angeles, Calif., 1988). These materials are made from a silicone anhydride.
There remains a need to continue to develop new materials which have novel electrical, electronic, and optical properties for use in the dissipation of spacecraft charging or electronic applications, for example.